• 한국대기환경학회지
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• 제16권2호
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• pp.141-150
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• 2000

In order to genralize the vertical dispersion of plume at long distances on mesoscale over complex terrain dispersion coefficients data have been obtained systematically according to lapsed time after release by using a composite turbulence water tank that simulates convective boundary layer. Dispersion experiments have been carried out for various combined conditions of thermal turbulence intensity mechanical turbulence intensity and plume release height at slightly to moderately unstable conditions. Results of tracer dispersion experiments conducted using water tank camera and image processing system have been converted into atmospheric dispersion data through the application of similarity law. The equation $\sigma$z/Zi=aX/(b+c X2)0.5 where $\sigma$2; vertical dispersion coefficient zi : mixing height X : dimen-sionaless downwind distance was confirmed to be an appropriate and general equation for expressing $\sigma$2 variation with turbulence intensity and plume release height, The value of "a" was found to be principally affected by mechanical turbulence intensity and that of "b" by mechanical turbulence intensity and release height. It was confirmed that the magnitude of "c" varies with release height. Results of water tank experiments on the relationship of $\sigma$2 vs downwind distance x have been compared with actual atmospheric dispersion data such as CONDORS data and Bowne's nomogram Operating conditions of a composite turbulence water tank for simulating the field turbulence situations of CONDORS experiments and Bowne's $\sigma$2(x) nomogram for suburban area have also been investigated in terms of water temperature difference between convection water tank and bottom plate heating tank grid plate stroke mixing water depth length scale and velocity scale. Moreover the effect of mechanical turbulence intensity on vertical dispersion has been discussed in the light of release height and downwind distance. height and downwind distance.

• 천문학회보
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• 제35권1호
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• pp.33.2-33.2
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• 2010

We have investigated a relationship among the solar proton events (SPEs), coronal mass ejections (CMEs) and solar flares during the solar cycle 23 (1997-2006). Using 63 SPE dataset, we found that SPE rise time, duration time, and decrease times depend on CME speed and SPE peak intensity depends on the CME earthward direction parameter as well as CME speed and x-ray flare intensity. While inspecting the relation between SPE peak intensity and the CME earthward direction parameter, we found that there are two groups: first group consists of large 6 SPEs (> 10,000 pfu at >10 MeV proton channel of GOES satellite) and shows a very good correlation (cc=0.65) between SPE peak intensity and CME earthward direction parameter. The second group has a relatively weak SPE peak intensity and shows poor correlation between SPE peak intensity and the CME earthward direction parameter (cc=0.01). By investigating characteristics of 6 SPEs in the first group, we found that there are special common conditions of the extremely large proton events (group 1); (1) all the SPEs are associated with very fast halo CME (>1400km/s), (2) they are almost located at disk region, (3) they also accompany large flare (>M7), (4) all they are preceded by another wide CMEs, and (5) they all show helmet streamer nearby the main CME. In this presentation, we will give details of the energy spectra of the 6 SPE events from the ERNE/HED aboard the Solar and Heliospheric Observatory (SOHO), and onset time comparison among the SPE, flare, type II burst, and CME.

• 대기
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• 제21권3호
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• pp.273-284
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• 2011

This study investigates the characteristics of satellite brightness temperature (TB) and rainfall intensity over the life cycle of convective cells. The convective cells in the three event cases are detected and tracked from the growth stage to the dissipation stage using the half-hourly infrared (IR) images. For each IR images the values of minimum, mean, and variance for the convective cell's TBs and the sizes of convective cells are calculated and also the relationship between TB and rainfall intensity are investigated, which is obtained using the pixel values of satellite TB and the ground rainfall intensity measured by AWS (Automatic Weather Station). At the growth stage of the convective cells, the TB's variance and cloud size consistently increased, whereas TB's minimum and mean consistently decreased. At this stage the empirical relationships between TB and rainfall intensity are statistically significant and their slopes (intercepts) in absolute values are relatively large (small) compared to those at the dissipation stage. At the dissipation stage of the convective cells, the variability of TB distributions shows the opposite trend. The statistical significance of the empirical relationships are relatively weak, but their slopes (intercepts) vary over life cycle. These results indicate that satellite IR images can provide valuable information in identifying the convective cell's maturity stage and in the growth stage, they may be used in providing considerably accurate rainfall estimates.

• 디지털융복합연구
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• 제15권1호
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• pp.527-536
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• 2017

연구는 체육계열 대학생이 인식한 경력개발지원과 구직강도의 관계에서 구직효능감의 매개효과의 관계를 규명하는데 목적이 있다. 이러한 연구 목적을 달성하기 위한 연구대상은 서울, 충남, 경상권에 소재한 대학교의 체육전공자 중 3, 4학년을 대상으로 223명의 자료를 수집하였다. 수집된 자료는 SPSS 20.0 프로그램을 이용하여 설문지의 신뢰도와 타당도검사, 상관분석을 실시하였으며, 경로분석은 AMOS 20.0 프로그램을 이용하여 분석을 실시하였다. 이러한 과정을 통해 얻어진 결과는 다음과 같다. 첫째, 체육계열 대학생이 인식한 경력개발지원은 구직효능감에는 통계적으로 정적인 영향을 미치고, 구직강도에는 통계적으로 유의미한 영향을 미치지 못했다. 둘째, 체육계열 대학생의 구직효능감은 구직강도에 통계적으로 정적인 영향을 미쳤다. 셋째, 체육계열 대학생이 인식한 경력개발지원과 구직강도 사이에서 구직효능감은 완전 매개효과가 있는 것으로 나타났다.

• 한국응용과학기술학회지
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• 제38권2호
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• pp.411-422
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• 2021

본 연구는 대학생을 대상으로 신체활동량에 따른 전공만족도와 대학생활적응과의 관계를 규명하는데 목적이 있다. 따라서 대학생 201명의 데이터를 확보하고, SPSS 22.0프로그램을 이용하여 기술통계분석, 신뢰도분석, 일원변량분석, 상관분석, 사후검증으로는 Tukey방법을 실시하였다. 분석결과는 첫째, 신체활동량에 따른 대학생의 전공만족도는 중강도신체활동집단과 고강도신체활동집단이 저강도신체활동집단 보다 통계적으로 유의하게 높은 것으로 나타났다(p<.05). 둘째, 신체활동량에 따른 대학생활적응은 고강도 신체활동집단이 중강도신체활동집단과 저강도신체활동집단보다 통계적으로 유의하게 높은 것으로 나타났다(p<.05). 마지막으로 대학생의 신체활동량, 전공만족도, 대학생활적응의 관계를 살펴본 결과 남학생의 경우 신체활동량과 전공만족도(일반만족), 대학생활적응(정서적응)에서 정적상관관계가 있고, 여학생의 경우 신체활동량과 대학생활적응(사회적응)에서 정적상관관계가 있는 것으로 나타났다(p<.05). 본 연구에서는 대학생의 신체활동량은 전공만족도와 대학생활적응과 관계가 있음을 확인하였다. 이와 같은 결론을 토대로 신체활동을 통해 대학생의 대학생활 관리를 도울 수 있을 것으로 기대한다.

• 한국기계가공학회지
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• 제14권2호
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• pp.112-120
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• 2015

In this study, the growth rate of surface cracks (da/dN) during the retardation period was analyzed in terms of effective stress intensity factor range(${\Delta}K_{eff}^*$) obtained by using the proposed effective plastic zone concept. Effective stress intensity factors obtained by using the effective plastic zone concept were smaller than those obtained by using Willenborg analysis. On the growth rate of surface cracks analyzed by ${\Delta}K$, the dependence of overload stress levels appears. On the growth rate by ${\Delta}K_{eff}$ obtained by Willenborg analysis, there is a linear relationship with two different slops between da/dN and ${\Delta}K_{eff}$. However, on the growth rate by ${\Delta}K_{eff}^*$ obtained by the proposed effective plastic zone concept, there is a linear relationship between da/dN and ${\Delta}K_{eff}^*$ that coincides with the results of constant amplitude loading.

• 천문학회보
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• 제38권2호
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• pp.88.2-88.2
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• 2013

Exploration of the wave-mode identification and its propagating property in the solar pore is desirable to study the energy transfer in the solar atmosphere. The Fast Imaging Solar Spectrograph (FISS) installed at the New Solar Telescope (NST) is a unique system that can do imaging of H-alpha and Ca II 8542 band simultaneously, which is quite suitable for studying of dynamics of chromosphere. In this study, we inspect a relationship between the cross-sectional area and intensity of the pore at continuum (-0.4 nm) near the Ca II line. We find coherent oscillations of the area and intensity. They shows out-of-phase (~ 180 degree difference) in photosphere, which implies that the oscillation is fast sausage mode. We also investigate a relationship between LOS velocities above the pore obtained from the Ca II and the Ha line cores, and find no significant difference of the phase (~10 degree) between the formation heights of the lines in chromosphere.

• 한국지구과학회지
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• 제34권1호
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• pp.102-106
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• 2013

동아시아 여름몬순의 강도와 북서태평양 여름몬순의 강도는 음의 상관을 갖는 것으로 알려져 왔다. 여기서 우리는 이 관계를 이용하여 북동아시아 여름철 강수의 잠재예측성을 조사하였다. 북서태평양 아열대 고기압은 북서태평양 여름몬순을 적절히 나타내며, 북서태평양-동아시아 지역 여름철 기후편차에 주된 성분이다. 그리고 북서태평양 아열대고기압 변동성을 이용한 북동아시아 여름철 강수 편차의 추정값은 북서태평양 여름몬순지수를 이용하는 것보다 더 낫다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1349-1353
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• 2003

Previous researches for fiber reinforced composite material(FRCM) have been evaluated the fatigue delamination behavior using the traditional fracture mechanics parameters. Therefore. previous researches for FRCM have not generally been firmed yet. Because delamination growth behavior in FRCM should be consider relationship between delamination area, A$\sub$D/ and crack length, a instead of traditional fracture mechanics parameters. Especially, in case of delamination behavior for FRCM without crack should be considering equivalent crack, i.e., pseudo crack, a$\sub$p/, using the fracture behavior of FRCM with crack. The major purpose of this study was to evaluate the delamination for FRCM without crack. The details of the studies are as follow : 1) Relationship between crack growth rate, da/dN and stress intensity factor, ΔK in FRCM containing a saw-cut and circular hole with crack. 2) Propose of PSEUDO CRACK MODEL for the delamination in FRCM without crack. 3) Analysis of crack propagation energy, E$\sub$crack/ using a total energy, E$\sub$total/ and delamination growth energy, E$\sub$del/.

• 한국자동차공학회논문집
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• 제12권5호
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• pp.58-65
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• 2004

A cylindrical constant volume combustion chamber was used to investigate the combustion characteristics of stratified methane-air mixture under several initial charge conditions in the author's previous reports. The results showed that the improvement of thermal efficiency and reduction of heat loss was realized simultaneously by using 2-stage injection method. This paper deals with the reason why the stratified combustion has showed better combustion rate through the measurement and analysis of chemiluminescence of C $H^{*}$ and $C_{2}$$^{*}$ radicals. An optic fiber bundle is used to measure the local emission of C $H^{*}$ and $C_{2}$$^{*}$ radicals to map the relationship between the excess air ratio and local radical intensity ratio in the combustion vessel at 5 mm apart form the geometric center. The results show that there exist a relationship between the intensity ratio and the air-fuel ratio. It is revealed that the improvement of combustion rate in a lean-stratified mixture is realized through the 2-stage injection method. method.